Fltk-editor has now been built on dCore with the latest source from the Git repo of Core. Code hinting is working. Seems an old version of fltk-editor was in dCore as it was taken straight from Core 5.x or earlier and not rebuilt.

As for feature additions, this app appears from the FLTK source and I don't have the time or inclination to delve into attempting changes. The goal is keeping with what is offered in Core.